In Germany the signaller can authorise the driver to pass a signal at danger by illuminating an auxiliary signal in the form of three white lights or a single flashing white light. On receiving this indication the driver then has permission to override the system which would normally stop the train if it passed a signal at danger.
This system can be used if the signaller believes that there has been a failure with the signalling system or to authorise an unusual shunting movement but obviously the signaller must be 100% confident that it is safe to do so. This confidence will come from complying with the rules and following a particular procedure. I assume that this is where mistakes were made with disastrous consequences.

Hi John that explains alot, thankyou.

(We've introduced a similar system over here recently. Called POSA (Proceed on Sight Authority), it's similar to a Ground Position Light and tells the driver that he can pass the signal at danger without any need to speak to the signaller).

BW.

Thanks for that, John.

I still have to say though, something just doesn't add up ...

Yes and after a decent night's sleep I've worked out what's bugging me.

If one of the drivers had been authorised to pass a signal at danger, he would have been travelling at a low speed and been prepared to stop short of any obstruction.

There's no defined speed for moving at caution but here in Blighty most drivers do about 15 mph ( the maximum speed for unmarked points & crossings). That way if we encounter a broken rail it won't be too damaging if the train derails & also we can't be done for not being cautious.

IIUC the tv & papers suggested that both trains were travelling at approximately 60 mph.

If the media has got it right - That's not the action of someone who has passed a signal at danger (with authority).

BW

Yes, I agree although I am tempted to think that the figure of 60 mph or 100 kph quoted in some reports might just be the maximum possible linespeed and that one of the trains could have been going slower.

A German train controller has been arrested over the February rail crash that killed 11 people in Bavaria, as prosecutors suspect he was distracted by a computer game at the time.

According to prosecutors he was playing the computer game on his mobile phone and made a signalling error, then dialled the wrong emergency number.
He has admitted that version of events, German media report.

http://www.bbc.co.uk/news/world-europe-36025951

Mobile phones can cause a lot of misery if used at an inappropriate time. We are not allowed to use them in the cockpit during critical periods of flight. I also never answer a telephone call or text while driving. Either pull off the road or call back later.

Wow, that's dreadful.

We seem to be receiving a picture of an incredibly sloppy setup. Of all the countries in Europe I wouldn't expect the Germans to be the lax ones.

It's inconceivable that in the 21st century a signalling system can allow 2 trains make a conflicting move onto a single line - even/especially with human intervention trying to override the inbuilt safety features. You just can't do that here for obvious reasons.

I still feel that one piece of the jigsaw puzzle is missing. It just doesn't quite ring true.

The thing that really bothers me here is the override signal that the German controller operated. We have 'override' signals here (POSAs), which authorise a driver to pass a signal at danger without having to speak to the signaller, but they shouldn't be located where a conflicting move can occur. A single line is THE number 1 conflict risk - so much so that we can't be authorised to pass a signal at danger that protects a single line. Instead working with a pilotman must be introduced.

And anyway if a driver moves under the authority of a POSA, it carries the same requirements of "Proceed with caution, be prepared to stop short of any obstruction and drive at a speed where you can stop in the distance you can see to be clear". Which in the UK usually means about 15 mph. The media is still reporting that both trains were doing considerably more. Surely one of them should have been crawling along ?

It's all very odd.

And mobile phones are a total nono here in the UK. ASLEF has mounted a campaign of its own to warn drivers that using a mobile phone in the leading cab of a moving train is a sackable offence and they can not defend a driver who has done so.

On the railway, mobile phones should not be used whilst performing any safety critical role.

A German train controller has admitted two errors that prompted two trains to collide head-on in Bavaria with the loss of 12 lives.

http://www.bbc.co.uk/news/world-europe-37936198

He may be liable for 5 years in jail, however I know nothing of the law in Germany, will the families sue him?